PyQt5 GUI需要的结构建议

Question

我正在编写一个用户界面的程序。我对Qt相当陌生，但我很享受使用它，特别感谢Qt设计师。程序应该如下：它有一个带有2个选项卡的主窗口。第一个选项卡是登录名，包含用户/密码字段和两个按钮“登录”和“退出”。 “退出”当然会退出应用程序，“登录”将尝试向服务器发送SOAP请求以进行登录。如果不成功，将显示一个带有错误的弹出窗口。如果成功，则显示带有成功消息的弹出窗口，并且激活并显示Tab2，其中用户可以插入一些数据（具有值取决于程序一旦连接到服务器就下载的一些表的组合框）。这里是一个修剪版本的代码：

class Ui_PopupError(object): 
    def setupUi(self, Dialog): 
     Dialog.setObjectName("Dialog") 
     Dialog.resize(322, 101) 
     self.label = QtWidgets.QLabel(Dialog) 
     self.label.setGeometry(QtCore.QRect(60, 20, 221, 16)) 
     self.label.setObjectName("label") 
     self.pushButton = QtWidgets.QPushButton(Dialog) 
     self.pushButton.setGeometry(QtCore.QRect(120, 60, 75, 23)) 
     self.pushButton.setObjectName("pushButton") 
     self.retranslateUi(Dialog) 
     self.pushButton.clicked.connect(Dialog.reject) 
     QtCore.QMetaObject.connectSlotsByName(Dialog) 
    def retranslateUi(self, Dialog): 
     _translate = QtCore.QCoreApplication.translate 
     Dialog.setWindowTitle(_translate("Dialog", "Dialog")) 
     self.label.setText(_translate("Dialog", "Wrong Username or Password. Try Again")) 
     self.pushButton.setText(_translate("Dialog", "Ok")) 
class Ui_PopupSuccess(object): 
    def setupUi(self, Dialog): 
     Dialog.setObjectName("Dialog") 
     Dialog.resize(322, 101) 
     self.label = QtWidgets.QLabel(Dialog) 
     self.label.setGeometry(QtCore.QRect(60, 20, 221, 16)) 
     self.label.setObjectName("label") 
     self.pushButton = QtWidgets.QPushButton(Dialog) 
     self.pushButton.setGeometry(QtCore.QRect(120, 60, 75, 23)) 
     self.pushButton.setObjectName("pushButton") 
     self.retranslateUi(Dialog) 
     self.pushButton.clicked.connect(Dialog.accept) 
     QtCore.QMetaObject.connectSlotsByName(Dialog) 
    def retranslateUi(self, Dialog): 
     _translate = QtCore.QCoreApplication.translate 
     Dialog.setWindowTitle(_translate("Dialog", "Dialog")) 
     self.label.setText(_translate("Dialog", "Successfully connected.")) 
     self.pushButton.setText(_translate("Dialog", "Ok")) 

class Ui_MainWindow(object): 
    def LoginMacro(self): 
     Username = self.Usernamefield.text() 
     Password = self.Passwordfield.text() 
     req = urllib.request.Request("server") 
     body = SOAPBody 
     response = urllib.request.urlopen(req, body) 
     try: 
      soup = BeautifulSoup(response.read(), 'html.parser') 
      testo = soup.get_text().strip() 
      tree = ET.fromstring(testo) 
      sessionid = tree.attrib['sessionid'] 
      self.popup = QtWidgets.QDialog() 
      self.popupui = Ui_PopupSuccess() 
      self.popupui.setupUi(self.popup) 
      self.popup.show() 
      self.tabWidget.setCurrentIndex(1) 
      self.Recap_Tab.setEnabled(True) 
     except: 
      self.popup = QtWidgets.QDialog() 
      self.popupui = Ui_PopupError() 
      self.popupui.setupUi(self.popup) 
      self.popup.show() 
    def setupUi(self, MainWindow): 
     MainWindow.setObjectName("MainWindow") 
     MainWindow.resize(798, 867) 
     #MainWindow created with QT Designer (long code...) 
     self.Exit.clicked.connect(MainWindow.close) 
     self.Login.clicked.connect(self.LoginMacro) 
     #This is an example of the value which should feed the combobox: 
     self.Handling_Type.addItems(REF_UDF_VALUES['udf_reference_value'][REF_UDF_VALUES['udf_cd']=='Handling Type']) 
    def retranslateUi(self, MainWindow): 
     _translate = QtCore.QCoreApplication.translate 
     MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow")) 
     #Retranslate created with Qt designer....(cut) 

if __name__ == "__main__": 
    import sys 
    app = QtWidgets.QApplication(sys.argv) 
    MainWindow = QtWidgets.QMainWindow() 
    ui = Ui_MainWindow() 
    ui.setupUi(MainWindow) 
    MainWindow.show() 
    sys.exit(app.exec_()) 

我只是想问你，如果这是做到这一点的正确方法。特别是，我在理解将“真实”事情（与服务器通信）的代码放在哪里的问题。例如，我将登录代码放在MainWindow类中，但我不确定这是否正常工作，因为我需要从该代码中捕获jsessionid，以便运行另一个下载表的代码。我应该把这个放在哪里？如果我把它放在代码的“try”部分，它会告诉我，当它试图在mainwindow中初始化组合框时，它不能找到参考表。我知道，我是一团糟！ :)

谢谢，对不起长问题！

Answer 1

与后端的通信应与GUI定义分开。我创建了一个名为API的独立类来处理请求/响应，并为我的QMainWindow创建一个API实例以供使用。这里我们想填充QComboBox与用户列表的例子：

class MainWindow(QMainWindow): 
    def __init__(self, parent=None): 
     super(MainWindow, self).__init__(parent) 
     self.ui = Ui_MainWindow() 
     self.ui.setupUi(self) 

     self.api = API() 

     users = self.api.get_users() 
     self.user_widget = self.ui.userCombo 
     self.user_widget.setModel(UserListModel(users, self)) 

class API: 
    def __init__(self): 
     self.base_url = 'http://localhost:5000/api' 
     self.users_url = '/users' 
     self.timeout = 5 

    def get_users(self): 
     try: 
      r = requests.get(self.base_url + self.users_url, timeout=self.timeout) 
     except ConnectionError: 
      print("Could not connect to API") 
      return API.make_default_user_list() 

     users = r.json(object_hook=API.api_hook_handler) 

     return users 

正如你所看到的，MainWindow不一样，如果用户的数据请求成功或失败在意。无论哪种方式，api.get_users()返回MainWindow可以使用的东西。